Transducer actuator arrays are known and are used to affect the physical world in some desired way, for instance creating a sound field in a room or a vibration pattern in a mechanical structure. Transducer sensor arrays are also known and are used to record disturbances of interest in the physical surroundings, such as sound or vibration, with some ability to separate the disturbances of interest from others. Typically such transducer arrays are controlled by suitable digital signal processing of the drive signals applied to actuator arrays or by suitable digital signal processing of the sensor signals received from the sensor arrays. The digital signal processing of these signals is computationally intensive and the invention aims to reduce this computational burden.